Reading about sensations recruits the posterior insula: An intracranial EEG study

Abstract

When we read, how do words and sentences become concepts? Contrary to theoretical perspectives that conceptualize meaning and concepts as symbolic and abstract, embodied approaches propose that semantic access relies on mental simulations of bodily experiences□associated with the word’s meaning (e.g., simulating the act of running when we read the word ‘run’ or feeling pain when reading the word ‘burn’). If this view of cognition underpins conceptual processing, then sensory and motor cortices should play an early role during language comprehension. To test this idea, we recorded intracranial neural activity (High-Frequency Activity, 50–150 Hz) in epileptic patients while they read short sentences from different semantic categories: abstract-, action- and sensation-related. We hypothesized that reading sensation-related sentences (e.g., “he burns me”) would preferentially involve the posterior insula — a key region for processing affective and painful sensations. Our results, revealed an early functional dissociation between the anterior and posterior insula: the anterior insula showed a non-selective response across all semantic categories, whereas the posterior insula presented an early selective response (around 170 ms) for the sensation-related ones. Furthermore, the intensity of this selective neural response in the posterior insula correlated with the intensity of subjective perceived pain. These results provide direct intracranial evidence suggesting that language is deeply rooted in body-environment interactions.